The EPA and other government agencies will use the tool to award Energy Star ratings

SPEC, the standards body for performance benchmarks, has released a new toolkit that should help customers choose the most energy-efficient server for the workloads they need to run.

SPEC's Server Efficiency Rating Tool will be used by the U.S. Environmental Protection Agency to provide efficiency data for an update to its Energy Star for Servers program that will roll out soon. Government agencies in other countries are expected to use it, too.

[ Get the latest practical info and news with Paul Venezia's Deep End blog. | Doing server virtualization right is not so simple. InfoWorld's expert contributors show you how to get it right in this 24-page "Server Virtualization Deep Dive" PDF guide. ]

With the cost of powering and cooling servers now higher in some cases than their initial purchase price, data center operators are looking more closely at how much electricity their equipment consumes and making purchase decisions accordingly.

The EPA already has an Energy Star program for servers, but the criteria it uses to rate systems is limited, including the efficiency of power supplies and how much power a server draws at idle. The SERT tool will provide much more detailed information.

The test involves running a dozen or more workloads that stress different server components, including CPU, memory and storage, and provides efficiency data for each workload at different levels of utilization.

"If a customer knows their application is going to be heavy on CPU and memory, for instance, he can look at the data and choose the most efficient server for that workload," said Klaus-Dieter Lange, who chairs the SPEC group that developed the tool.

The EPA will employ labs around the country to run the tests and start collecting data in about two weeks, which it will then post to its website soon after.

SERT can test both x86 and IBM Power servers with up to eight processors, as well as multinode servers. SPEC hopes to expand the tool soon to include ARM- and Sparc-based servers, Lange said.

The group spent three years developing SERT with input from nearly all the big server vendors. Server makers view it with a mix of trepidation and enthusiasm, because it will shine a spotlight on the efficiency of their systems, but also help show off any engineering achievements.

"The server vendors will be forced to design more efficient servers, not just for CPU-intensive workloads but also for memory and storage as well," said Lange.

An Energy Star rating is required for equipment sold to the public sector, so the vendors will have to get their systems tested if they want to sell in those markets.

SPEC's biggest challenges were choosing the right workloads -- or worklets, as it calls them -- to make the tests relevant to a lot of customers, and designing a test suite that the certification labs can run quickly and consistently, without needing specialized engineering skills. SERT has a simple GUI and prebuilt tuning options to make sure tests will be conducted uniformly.

SPEC and the EPA are still figuring out how they'll use the data to rank servers. With the current tests, they choose the top 25 percent of servers and award them an Energy Star. Because the new test is more complicated, they'll collect data for nine months and use it to figure out how to rank the systems. But buyers will be able to start using the results as soon as they're posted.

James Niccolai covers data centers and general technology news for IDG News Service. Follow James on Twitter at @jniccolai. James's email address is james_niccolai@idg.com.